The present invention relates to a conveyance means provided in a sorter which is combined with an image forming apparatus so as to sort recording sheets discharged from the apparatus.
In general, as shown in FIG. 2, a sorter is combined with an image forming apparatus 1 and functions as follows: recording sheets 5 discharged from the image forming apparatus 1 are conveyed by a conveyance means provided in a conveyance section 18 in the aforementioned sorter 10 and sorted by a changeover gate so that the sorted recording sheets 5 can be sequentially put into numerous bins 20 which are provided in the sorter 10.
As illustrated in FIG. 3, the conveyance section of the aforementioned sorter 10 conveys the aforementioned recording sheets 5 to the first bin 20a through a changeover gate 21a. The recording sheets 5 are conveyed and sorted into bins 20 including the first bin 20a installed in the sorter 10 by the first and second belt conveyance mechanisms 18, 19 through changeover gates 21 and the aforementioned changeover gate 21a.
As illustrated in the drawing, the aforementioned first belt conveyance mechanism 18 is composed of an upper roller 12 and a lower roller 13 which are vertically arranged being rotatably supported by side plates of the sorter 10, and an endless conveyance belt 14 is wound around the upper and lower rollers 12, 13.
The aforementioned lower roller 13 is driven by a drive unit 25 provided in the aforementioned sorter 10 so that the aforementioned conveyance belt 14 can be vertically rotated. The second belt conveyance mechanism 19 is installed above the first belt conveyance mechanism 18. In a non-sorting operation, all of the aforementioned recording sheets are conveyed to the aforementioned first bin 20a through the changeover gate 21a. Usually, the conveyance means, changeover gate and bins are used both in a non-sorting operation and a sorting operation. Consequently, in a sorting operation, recording sheets 5 are conveyed to a predetermined bin by changing over the changeover gate 21a and gates 21, wherein the changeover gate 21a is utilized not only for sorting recording sheets to be put into the first bin 20a but also for sorting recording sheets to be put into other bins 20, and wherein the gate 21 is exclusively used for sorting recording papers to be put into the corresponding bin.
The second belt conveyance mechanism 19 which is also utilized in a non-sorting operation, is composed in such a manner that: a roller 12a which is pushed by a spring against the circumferential surface of the upper conveyance roller 12 of the aforementioned first belt conveyance mechanism 18, and a roller 26 which is disposed on the left of the roller 12a, are rotatably supported by side plates of the aforementioned sorter 10; and an endless flat belt 27 is wound around the rollers 26 and 12a. A pinch roller 28 is installed below the aforementioned roller 26, and pressed against the roller 26 through the conveyance belt 27, so that the torque of the roller 26 can be transmitted to the pinch roller 28.
The second belt conveyance mechanism 19 is driven in such a manner that: an exclusive drive unit 29 drives the aforementioned drive roller 26; and the torque of the drive roller 26 is transmitted to the aforementioned rollers 12a and 28.
The recording sheet 5 which has been conveyed into the aforementioned sorter 10 by the aforementioned upper roller 12 and roller 12a, passes through a passage 16a formed by the aforementioned changeover gate 21a provided between the upper roller 12 and the drive roller 26, and the lower surface of the aforementioned belt 27, and then the recording sheet 5 is pinched between the aforementioned roller 26 and the pinch roller 28 through the flat belt 27 so as to be successively conveyed into the aforementioned bin 20a.
As explained above, in a conventional sorter, the second belt conveyance mechanism, which is also used in the case of a non-sorting operation, is used so as to positively convey recording sheets to the first bin.
As explained above, the above-described paper discharging rollers are driven by an exclusive drive unit or other drive units, and torque is transmitted to idle rollers from the driven paper discharging rollers, so that the mechanism is very complicated and the cost is increased.
The first object of the present invention is to provide a sorter having a simple and low-cost conveyance means in which the aforementioned problems can be solved.
As described above, the first belt conveyance mechanism 18 of the conventional sorter is provided with numerous guide rollers 15a, so that the conveyance mechanism is complicated and the cost is increased, and further a loud noise is made when the sorter is operated. The second object of the present invention is to solve the aforementioned problems and to provide a simple and low-cost sorter having guides for a conveyance belt, in which recording sheets can be stably conveyed without making a loud noise.